Metering hypodermic syringe



Nov. 12, 1963 F. CISLAK METERING HYPODERMIC S YRINGE Filed July 20, 1961 INVENTOR. FRANK C ISLAK nited States Patent 3,119,319 HYBGDEBMKC SYRTNGE Franlr Qislair, Riverside, ill assignor to Ideal lnsh'ument Z: Mfg. 60., line, Chicago, ill, a corporation of lllinois Filed duly 29, 196i, Ser. No. 125,537 4 Claims. (Cl. 123-218) This invention relates generally to hypodermic syringes and more particularly to a veterinary syringe for the administration of a plurality of drug doses of selective voltime from a single loading of the syringe.

Syringes of the multiple-dose type which are capable of delivering repeated or successive doses have become relatively well known in recent years. Such syringes have found extensive use in the treatment of livestock and other animals, and particularly in situations where it is required to treat large numbers of animals with the same serum or other medication. Although numerous syringes of the general type under consideration have heretofore been provided, they have nonetheless been characterized by a variety of disadvantageous features.

In general, the prior syringes comprised a relatively large ampule or cylinder having a plunger or piston reciprocably positioned therein. Actuating means were provided for reciprocating the piston to eject the contents of the cylinder from a cannula needle connected to the front end of the cylinder. Some of the prior devices had no metering means whatever, but depended instead upon the skill and judgment of the operator to obtain consistent dosages with each successive injection. Those prior devices were objectionable for obvious reasons. More recently, metering means have been provided which were likewise deficient in one respect or another. Thus, for example, some of the prior metering means were not adjustable but delivered only a single fixed dosage, while others could be adjusted to deliver only two or three different dosages. The majority of the prior metering means were quite complex and had many moving parts which were subject to breakdown. In addition, the complexity of the metering means added greatly to the cost of the entire syringe.

It is, therefore, an important object of this invention to provide a metering hypodermic syringe which overcomes all of the above-described disadvantages.

Another object is to afford a metering hypodermic syringe of the character described having greatly simplified metering means.

A further object is to provide a metering hypodermic syringe of the character described having metering means adjustable to deliver live or even more different dosages.

Still another object is to aiford a metering hypodermic syringe of the character described having metering means which may be simply and quickly adjusted to deliver the desired dosage. A related object is to afford such a syringe in which the individual dosage may be varied during a single filling of the syringe.

Yet another object is to provide a metering hypodermic syringe of the character described which is in the form of a pistol so that the same may be conveniently and efficiently operated with only one hand.

Still a further object is to atlord a metering hypodermic syringe of the character described in which the actuating means for the piston is automatically retracted with each release of the pistol trigger. The piston thus may be readily retracted for purposes of refilling the cylinder with medication without requiring any further manipulation of the syringe.

Yet a further object is to provide a metering hypodermic syringe of the character described which may be inexpensively fabricated due to the simplified construction thereof, and yet is most durable and efficient for the purpose intended.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel features of construction, arrangement and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportion, size and minor details of the structure may be made without departing from the spirit or sacrificing any of the advantages of the invention.

For the purpose of facilitating an understanding of my invention, 1 have illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, my invention, its mode of construction, assembly and operation, and many of its advantages should be readily understood and appreciated.

Referring to the drawings in which the same characters of reference are employed to indicate corresponding or similar parts throughout the several figures of the drawings:

PEG. 1 is a side elevational View of a metering hypodermic syringe embodying the principles of the invention with a portion being broken away to show internal construction;

FIG. 2 is a fragmentary elevational view taken from the opposite side of the syringe;

FIG. 3 is a fragmentary top plan View;

FIG. 4 is a fragmentary sectional View taken on the plane of line 4-4 and viewed iin the direction indicated; and

FIG. 5 is an exploded perspective View showing the elements of the metering means and the actuating means.

Referring now to FIG. 1 of the drawings, the reference numeral it indicates generally a metering hypodermic syringe embodying the principles of the invention. The syringe is in the general form of a pistol and comprises a stationary handle 12 having an upwardly and rearwardly extending segment 14 which terminates in a circular eye At its forward end, the stationary handle 12 is provided with an enlarged internally threaded collar 18, the centers of said collar and eye 16 being in aligned relationship.

A cylindrical casing 2d having an externally threaded portion 22 is removably threaded in the collar 18. The front of the casing 29- is provided with a suitable connector 24 for removably accommodating a cannula needle such as 26. The casing 29 may be formed with a pair of windows such as 2-3 for viewing the interior of a transparent cylindrical tube 3i) which is nicely fitted within the easing to afford the syringes ampule or cylinder. T he tube 3% may be made of glass or the like for ease of cleaning and Wear-resistance, although the casing 29 could, if desired, be made without the windows 28 to afford the am pule without the need for the tube 3% Reciprocably positioned within the tube 3%} is a piston 32. An elongated rod 34 is connected to the piston 32 and journallcd through the eye 16. The rear end of the rod 34 is provided with an enlarged diameter knob as, and a medial portion thereof is formed with a rack 33 having a plurality of equally spaced teeth 46. A cap member 42 seals the rear of the tube 3%, said cap member sing formed with a central aperture to accommodate the rod 34 therethrough.

A movable handle 44 is pivotally connected to the stationary handle 12, and said movable handle may be provided with a finger grip such as 46 for facilitating the gripping thereof. A coil spring d7v is mounted between the handles 12 and 44 to normally urge the same apart. The movable handle 44 terminates reanwa-rdly in a slotted member 48 within which is pivotally mounted a pawl 549 (see FIG. 5). The member 48 and pawl 50 are formed 9 with bores 52 and 54 respectively and a spring 56 is positioned in said bores to normally urge the front of said pawl upwardly into engagement with the teeth id of the rack 38.

It is important to note that the pawl 50 is formed with an arcuate cam surface 53. Cooperating with the cam surface 58 is a pointed cam pin ea mounted on the inner surface of the handle segment 14. When the handle 44 is rotated or squeezed, the upwardly urged pawl d engages one of the rack teeth 40 and forces the piston 31; forwardly in the tube 30. However, when the handle 4% is released, the coil spring 47 forces the pawl cam surfate 555 against the cam pin 6%. This camming action causes the pawl 5a to rotate out of en agement with the rack teeth 4% as indicated in FIG. 4 of the drawings. The rod 34 thus may be readily retracted by grasphtg the knob 36 for purposes of refilling the tube 3% as desired. Similarly, the entire contents of the tube 3%} may be emptied for a single injection, if desired, by simply manually pushing the rod 34 forwardly.

Novel metering means, indicated generally by the numeral 65, is mounted on the slotted member 48. The metering means 65 comprises a metering plate on rotatably connected in abutting relationship to a swivel plate 68. The swivel plate 63 is retained against rotation on the member 4-3 by any suitable means such as dowel pins, and a suitable multi-diameter screw such as 7% may be provided for connecting the metering plate 65, swivel plate 68 and pawl 59 to the slotted member 58 (see FIG. 5). A spring 72 is positioned in a bore 74 formed in the adjacent wall of the member 48 and said spring extends through an aligned aperture 75 in the swivel plate 58 to urge an indexing ball 78 against the metering plate 66. Cooperating with the indexing ball 73 is a plurality of ball seats 89 formed in the inner surface of the metering plate 66 and circularly spaced around a mounting aperture 51. It will thus be appreciated that the plate may be readily indexed by simply rotating the same against the pressure of the spring 72 until the ball 78 is seated in the desired ball seat 80.

It is important to note that the metering plate 66 is fonmed with a plurality of side edges, the number of which corresponds to the number of difierent dosages injectable by the syringe. In the embodiment illustrated, the metering plate has five side edges 82, 34, 86, 33 and 9%, so that the syringe it) is adjustable for five different dosages. There are likewise five ball seats 8%, one for each of the metering plate side edges. It should be noted, however, that although the metering plate 66 is generally pentagonal in configuration, the side edges differ from each other in shape and/or size. Thus, for example, the edge 82 is arcuate, while the straight edge 83 is much shorter than the straight edge ii. In addition, the mounting aperture 81 Which affords the axis of rotation for the metering plate 66 is elf-center. The importance of this construction will become apparent as the description proceeds.

Each of the side edges 82, 84, S6, 38 and 9t) is marked with a dosage calibration 1, 2, 3, 4 and 5 respectively, as illustrated in FIG. 1 of the drawings. The said dosage calibrations may correspond to any convenient unit of measurement, such as cubic centimeters or milliliters. Similarly, the tubeSd preferably is dimensioned, and the rack teeth 46' preferably are spaced so that the forward movement of the piston 32 through the distance of one tooth 40 will result in a dosage of the same unit measure ment.

The operation of the metering means 65 may now be described as follows. If a dosage of 1 cc. is desired, the metering plate 66 is indexed so that the side edge 82 thereof is closest to the cap member 42 (see H6. 1). When the handle 44 is squeezed, the pawl 5h engages one of the rack teeth 4d and moves the rod 34 forwardly. However, the rod 34 can be moved forwardly only until the edge 82 abuts the cap member 42 (see FIG. 3). The

forward stroke of the piston 32 thus is limited to the length of one rack tooth id, or sufiicient to produce an injection of 1 cc. in the same manner, the metering plate 66 may be indexed for any other dosage, and the length of the forward stroke will then be limited by the particular side edge which abuts the cap member 42. Since the configuration of the plate 6% is irregular and the same rotates about an oil-center axis, the side edges 84, 86, 83 and 9% permit the rod 34 to be moved forwardly a successively greater distance with each squeeze of the handle before the particular side edge abuts the cap member 42 (see FIG. 2, for example, wherein the metering plate 66 is set for a dosage of 5 cc.).

From the above description and drawings, it should be apparent that i have provided a novel metering hypodermic syringe which is most efficient and simple to operate. It will, of course, be appreciated that while the syringe has been illustrated and described as having five dosage settings, the novel metering means maybe changed in design to afiord more or less settings as desired, it being necessary only to suitably change the number and shape of the metering plates side edges. In addition, the pawl is automatically disengaged from the rack after each injection, and the greatly simplified metering means permits the entire syringe to be inexpensively manufactured.

It is believed that my invention, its mode of construction and assembly, and many of its advantages should be readily understood from the foregoing without further description, and it should also be manifest that while a preferred embodiment of the invention has been shown and described for illustrative purposes, the structural details are nevertheless capable of Wide variation within the purview of my invention as defined in the appended claims.

What 1 claim and desire to secure by Letters Patent of the United States is:

1. in a pistol-type hypodermic syringe including a fluid cylinder, a piston in said cylinder, a rack connected to said piston, a trigger handle, and a pawl on said trigger handle cooperating with said rack; the improvement comprising a metering plate mounted on said trigger handle in parallel relationship therewith and movable with said pawl, said metering plate being indexable and cooperating with said cylinder 'to selectively limit the forward stroke of said piston with each operation of said trigger handle, said metering plate having a plurality of side edges of varying length and configuration, said metering plate being mounted to rotate around an oil-center axis, said side edges adapted to abut the back of said cylinder to selectively limit the forward stroke of said piston varying pro-determined distances.

2. The metering hypodermic syringe of claim 1 in which a swivel plate is secured to said trigger handle, said metering plate being mounted in abutting relationship on said swivel plate, a spring loaded indexing ball in said swivel plate bearing against said metering plate, and a plurality of ball seats formed in said metering plate in radially spaced relationship about said axis of rotation, whereby said metering plate may be selectively indexed so that each operation of said trigger handle will deliver a desired pro-determined dosage.

3. A pistol-type metering hypodermic syringe comprising a frame including a stationary handle, a cylinder for receiving a fluid removably mounted forwardly on said frame, a cap member closing the rear of said cylinder, a piston reciprocably positioned in said cylinder, an el0n gated rod connected to said piston and projecting rearwardly through said cap member, a medial portion of said rod being formed with teeth to afford a rack, a trigger handle pivotally connected to said stationary handle, spring means normally urging said handles apart, said trigger handle terminating rearwardly in a slotted segment, a pawl mounted in said slotted segment and spring biased into normal engagement with said rack, and an indexable metering plate rotatably mounted on a side surface of said slotted segment in parallel relationship with said trigger handle and in alignment with said cap member, said metering plate having five side edges 0d? varying length and configuration, said side edges adapted to abut said cap member when said trigger handle is squeezed, said metering plate being rotatable around an off-center axis, whereby each of said side edges limits the forward motion of said pawl and rack a varying predetermined distance.

4. The metering hypodenmic syringe of claim 3 in which said pawl is formed with a rear cammin g surface, a camming pin secured to said stationary handle in alignment with said camming surface, whereby said pawl is automatically disengaged from the teeth of said upon the release of said trigger handle.

References Cited in the file of this patent UNITED STATES PATENTS Mead Apr. 6,

Miller Oct. 25,

Dann June 19,

Sturtz June 30,

Bruchhaus Aug. 28,

FOREIGN PATENTS Germany June 15,

Germany Mar. 10,

rack 

3. A PISTOL-TYPE METERING HYPODERMIC SYRINGE COMPRISING A FRAME INCLUDING A STATIONARY HANDLE, A CYLINDER FOR RECEIVING A FLUID REMOVABLY MOUNTED FORWARDLY ON SAID FRAME, A CAP MEMBER CLOSING THE REAR OF SAID CYLINDER, A PISTON RECIPROCABLY POSITIONED IN SAID CYLINDER, AN ELONGATED ROD CONNECTED TO SAID PISTON AND PROJECTING REARWARDLY THROUGH SAID CAP MEMBER, A MEDIAL PORTION OF SAID ROD BEING FORMED WITH TEETH TO AFFORD A RACK, A TRIGGER HANDLE PIVOTALLY CONNECTED TO SAID STATIONARY HANDLE, SPRING MEANS NORMALLY URGING SAID HANDLES APART, SAID TRIGGER HANDLE TERMINATING REARWARDLY IN A SLOTTED SEGMENT, A PAWL MOUNTED IN SAID SLOTTED SEGMENT AND SPRING BIASED INTO NORMAL ENGAGEMENT WITH SAID RACK, AND AN INDEXABLE METERING PLATE ROTATABLY MOUNTED ON A SIDE SURFACE OF SAID SLOTTED SEGMENT IN PARALLEL RELATIONSHIP WITH SAID TRIGGER HANDLE AND IN ALIGNMENT WITH SAID CAP MEMBER, SAID METERING PLATE HAVING FIVE SIDE EDGES OF VARYING LENGTH AND CONFIGURATION, SAID SIDE EDGES ADAPTED TO ABUT SAID CAP MEMBER WHEN SAID TRIGGER HANDLE IS SQUEEZED, SAID METERING PLATE BEING ROTATABLE AROUND AN OFF-CENTER AXIS, WHEREBY EACH OF SAID SIDE EDGES LIMITS THE FORWARD MOTION OF SAID PAWL AND RACK A VARYING PREDETERMINED DISTANCE. 